Meter pits are generally known in roto-molded (from a rotational molding process) configurations. Due to these types of forming processes, the thickness of the walls of meter pits is often substantially uniform. Although the walls may be uniform, the stresses or design requirements in different parts of the meter pits may not be. This may result in too much material being used which is both wasteful and expensive. For example, U.S. Pat. No. 6,164,131 to Edwards shows an in-ground receptacle for fluid and meter valves which uses “a continuous wall” that is “co-molded in three layers” (Abstract). As can be seen in the figures of Edwards, (e.g. FIG. 2) the wall thickness is substantially uniform throughout. This results in wasted and inefficient use of material.
Meter, valve and other types of pits are typically buried in the ground where the footing of the meter pit is directly in contact with soil. The footing therefore needs to be wide enough to resist the tendency of the meter pit to settle further into the ground, which could damage the meter and/or plumbing.
Furthermore, meter pits (for municipal usage which are substantial in size and have demanding performance requirements, as opposed to those for lawn sprinklers which are relatively small and have minimal if any performance requirements) often require a crush force resistance of 20,000 Pounds Force (to support incidental vehicle traffic) which can dictate a wall thickness at the weakest point of the pit which in the roto-molding process would essentially require more or less a uniform thickness of the pit, which may not be ideal use of material, resulting in wasted material and increased cost.
In some cases, the footing is formed by folding over a sheet associated with the pit to create a flange extending outwardly from the wall of the pit. Although this may help prevent settling, when the flange is buried in the ground, it may be very difficult to remove or adjust the pit due to the flange being buried.
Prior art meter pits also suffer a disadvantage in that they commonly require post molding processing to form the final product. For example, some meter pits include holes at the bottom that allow plumbing lines to enter and exit there from. Roto-molded pits often require post molding cutting operations to open these holes. Such pits also need the primary top and bottom holes cut out which is a greater effort and a considerable waste of material. Potentially 10-25% or more of scrap that may not be reusable in another pit, often times because the roto-molding process is done with two plastics or two colors with the inside being white and the outside being black which means the waste may not be useful due for re-molding as the re-melted product would not be a combination of the two colors (i.e. grey).
It is therefore desirable to provide an improved meter pit that uses less material than prior art versions, avoids the tendency to settle further into the ground, reduces or eliminates post molding processing requirements and is strong and stiff enough to remain in operation.